PRECIA MOLEN Unique Lightning Protection System
Updated: Aug 27, 2018
Weighbridges are vulnerable to damage by lightning strikes. The consequence of such strikes can be very expensive to repair, therefore weighbridge manufacturers now to offer lightning protection systems.
Do these protection systems work? In most cases the answer is, No! But why do they not work? The answer becomes obvious only when the behaviour of lightning is understood.
What is a lightning strike?
There are various types of lightning flashes, but the one we are usually concerned about is the dramatic forked lightning, that strikes the earth with a dramatic bang! It is caused when the electrical charge in a thunder cloud builds up to such a level that a 'spark' jumps from the cloud to earth to dissipate the huge imbalance of energy.
The power in a typical lightning strike is approximately 10 million mega-watts. There is on average four strikes per lightning flash, each strike lasting about 30 micro-seconds. 10 million mega-watts equates to the combined power output of say 10,000 power stations.
Can lightning strikes be prevented?
No! It is impossible to stop lightning occurring! Even if it were possible to remove all the vulnerable features from the landscape, a thunder cloud's electrical charges would eventually build up to such a magnitude that the energy would have to be dissipated into the flat ground.
To defeat the enemy........understand how he operates.
Having seen the futility of trying to defend a weighbridge against the extremely rare direct lightning strike of 10 million mega-watts, and having recognised the basic mechanics behind most common form of lightning related damage, Precia Molen have developed a radically different design. Central to this design is the principle of protecting the load cells from the large ground potentials generated by a lightning strike. An insulating component is fitted between the ground and each load cell. The dielectric properties of the component are such that for the duration that a lightning induced potential gradient exists in the ground under the weighbridge, the potential across the weighbridge and its load cells remains comfortably below the 100 volt threshold.
The component's dielectric strength is greater than 5 million volts per metre!!
This component has been proven to be structurally strong enough to support the weighbridge through all the years of use under very arduous conditions. First used nearly ten years ago, it has now been fitted on well over a thousand weighbridges in countries around the world.
Whilst it is impossible to prove its effectiveness on the basis that no-one knows if a weighbridge would have been damaged had the protection not been fitted, it is a fact that the number of Precia Molen weighbridges fitted with the protection system that have been damaged by lightning is virtually zero. There have even been examples of sites where weighbridges from more than one manufacturer have been in operation and only the Precia Molen weighbridge has escaped the effects of lightning damage.
The Precia Molen system is probably the only system in the world that works, and this is because it has approached the problem from the right direction.